NTT DoCoMo has shelved plans for a March launch of a smartphone featuring a new operating system called Tizen, dealing a blow to one of the platform's key backers - Samsung

Japan's largest mobile carrier said Friday that the Japanese smartphone market wasn't growing fast enough for it to support a third mobile operating system, a reference to Apple's iOS operating system and Google's Android, which powers the majority of Samsung's devices. In explaining its decision, DoCoMo cited research by IDC Japan showing the country's smartphone market in the April-to-September period grew only 2.2% from a year earlier.

"The market is not big enough to support three operating systems at this time," DoCoMo spokesman So Hiroki said Friday.